Sleep as the Foundation of Brain Health.

Sleep is a vital function, taking about one-third of a human lifetime, and is essential for achieving and maintaining brain health. From homeostatic neurophysiology to emotional and procedural memory processing to clearance of brain waste, sleep and circadian alignment remain paramount. Yet modern lifestyles and clinical practice often dismiss sleep, resulting in profound long-term repercussions. This chapter examines the roles of sleep and circadian rhythms in memory consolidation, synaptic plasticity, and clearance of metabolic waste, highlighting recent advances in neuroscience research. We explore how insufficient and disordered sleep-a public health concern-can impair cognition, escalate neurodegenerative risks, and compromise neurovascular integrity, thereby impacting brain health. These findings underscore the need for comprehensive screening for disturbed sleep and targeted interventions in clinical practice. Emerging interventions and AI-driven technologies may allow early detection and personalized and individualized treatments and improve outcomes. Overall, this chapter reaffirms that healthy sleep is indispensable at any level of neurological disease prevention-on par with the role of diet and exercise in cardiovascular health-and represents the foundation of brain health.